title: Acute appendicitis: investigating an optimal outer appendiceal diameter cut-point in a pediatric population.
abstract: BACKGROUND
  Acute appendicitis is the most common cause of abdominal pain in children requiring operative intervention. Among a number of sonographic criteria to aid in the diagnosis of appendicitis, an outer diameter >6 mm is the most objective and widely accepted. However, there is a lack of evidence-based standards governing this consensus.
  
  
  OBJECTIVE
  The aim of this study was to determine the outer appendiceal diameter that maximizes sensitivity and specificity in a pediatric population.
  
  
  METHODS
  A retrospective review of all urgent diagnostic ultrasounds (US) was performed over 2 years in children aged <18 years. The diagnostic accuracy of various cut-points was assessed by calculating the sensitivity and specificity and plotting a receiver operating characteristic (ROC) curve.
  
  
  RESULTS
  The study sample consisted of 398 patients in whom the appendix was visualized on US. The median outer appendiceal diameter was significantly higher in the surgical group compared to the nonsurgical group (9.4 mm; range = 8.1-12.0 vs. 5.5 mm; range = 4.4-6.5, p < 0.01). The optimal cut-point with the greatest area under the ROC curve was determined to be an outer appendiceal diameter of 7.0 mm.
  
  
  CONCLUSIONS
  In our patients, adopting a 7-mm rather than a 6-mm appendiceal diameter threshold would balance a greater number of missed cases of acute appendicitis for a reduction in the number of unnecessary surgeries.
authors.affiliation: Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Prendergast
authors.affiliation: Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Pediatrics and Medicine, Children's Hospital at London Health Sciences Centre, London, Ontario, Canada.
authors.forename: Naveen
authors.initials: N
authors.lastname: Poonai
authors.affiliation: Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Pediatrics and Medicine, Children's Hospital at London Health Sciences Centre, London, Ontario, Canada.
authors.forename: Tim
authors.initials: T
authors.lastname: Lynch
authors.affiliation: Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Medical Imaging and Radiology, Children's Hospital at London Health Sciences Centre, London, Ontario, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: McKillop
authors.affiliation: Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Pediatrics and Medicine, Children's Hospital at London Health Sciences Centre, London, Ontario, Canada. Electronic address: rod.lim@lhsc.on.ca.
authors.forename: Rodrick
authors.initials: R
authors.lastname: Lim
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012372:ROC Curve; D012016:Reference Values; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography
keywords: appendicitis; diagnosis; pediatric; ultrasound